Birds & Science >
Colorado IBAs
Denver City Park Lakes
Denver County
Size: 24 surface-acres (Ferrill Lake), 5.5 surface-acres (Duck Lake), ~.75-1.5 acres (islands)
Elevation: 5280 feet
Habitats:
Primary – open water
Secondary – island with trees
Ownership:
Municipal (City of Denver)
Land Use:
Primary – recreation/tourism, water supply
IBA Criterion: 4 (heronries)
Site description
Location:
The two lakes (Ferrill and Duck) which comprise this site are located within Denver City Park, in east Denver. The Denver Zoo lies north of Duck Lake, while the Denver Museum of Nature and Science is one-half mile northeast of Ferrill Lake.
Vegetative/natural features:
Ferrill and Duck Lakes are man-made lakes, each with a treed island in the center.
Ornithological Importance
Ferrill Lake has, and Duck Lake has or has had, a closely-packed colony of Black-crowned Night Herons and Double-crested Cormorants. The colony of night herons probably has more nests than any in Colorado.
Breeding species:
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Average #
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Maximum #
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Black-crowned Night Heron
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100 pairs
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150 pairs
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Double-crested Cormorant
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50 pairs
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100 pairs
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Yellow-crowned Night Heron
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1 pair
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Conservation/Management Issues
Minor threats:
- introduced animals (Canada geese);
- pollution from the heron colony;
- disturbance to birds and habitat from heavy recreational use of City Park.
Management details:
While City Park permits paddle-boats and canoes on Ferrill Lake, they do not permit motorized boats. Water is supplied to Ferrill Lake through the City Ditch from the South Platte River from May through October. Park managers use this water as irrigation to water the park grounds. The water level drops dramatically during the off-season (November through April). Ferrill Lake will likely be completely drained in 2001 to fix the electric fountain located in its center.
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